function fizzBuzz(num) {
    if (num % 3 == 0 && num % 5 == 0)
        return "fizzbuzz";
    else if (num % 3 == 0)
        return "fizz";
    else if (num % 5 == 0)
        return "buzz";
    else if (num == null || typeof num != "number")
        return false;
    else return num;
}